High pressure expansible chamber device

ABSTRACT

The invention relates to an expansible chamber type of device which is especially adapted for use with high pressure operating fluids. The device has a valve which directs pressurized fluid from an inlet port to the expanding chambers thereof and nonpressurized fluid from the contracting chambers thereof to an outlet port. A valve sealing arrangement is provided whereby pressurized fluid is utilized to bias the valve into sealing engagement with a valve block which contains passages leading to the expanding and contracting chambers. A main feature is that the inlet and outlet ports are reversible from the standpoint that either port may be used as the inlet port to obtain a desired direction of rotation without adversely affecting the operativeness of the sealing arrangement. Another feature is that the valve biasing forces are balanced so that the net force which biases the valve is only slightly larger than the axially directed opposing force regardless of the direction of rotation of the main shaft of the device.

United States Patent [1 1 Easton HIGH PRESSURE EXPANSIBLE CHAMBER DEVICE [76] Inventor: Wayne B. Easton, 3001 W. 96th St.

Cir., Bloomington, Minn. 55431 [22] Filed: Jan. 10, 1974 [21] Appl. No.: 432,196

[56] References Cited UNITED STATES PATENTS 8/1972 Easton 418/270 7/1973 Woodling 418/61 B Primary Examiner-John J. Vrablik [57] ABSTRACT The invention relates to an expansible chamber type June 3, 1975 of device which is especially adapted for use with high pressure operating fluids. The device has a valve which directs pressurized fluid from an inlet port to the expanding chambers thereof and non-pressurized fluid from the contracting chambers thereof to an outlet port. A valve sealing arrangement is provided whereby pressurized fluid is utilized to bias the valve into sealing engagement with a valve block which contains passages leading to the expanding and contracting chambers. A main feature is that the inlet and outlet ports are reversible from the standpoint that either port may be used as the inlet port to obtain a desired direction of rotation without adversely affecting the operativeness of the sealing arrangement. Another feature is that the valve biasing forces are balanced so that the net force which biases the valve is only slightly larger than the axially directed opposing force regardless of the direction of rotation of the main shaft of the device.

3 Claims, 4 Drawing Figures HIGH PRESSURE EXPANSIBLE CHAMBER DEVICE The invention relates to an expansible chamber type of device which is especially adapted for use with high pressure operating fluids. Such devices commonly have a valve which directs pressurized fluid from an inlet port to the expanding chambers thereof and nonpressurized or spent fluid from the contracting chambers thereof to an outlet port.

A sealing arrangement must be provided for and in connection with such a valve to prevent or deter the short circuiting of pressurized fluid from the high pressure side to the low pressure side or from the high pressure side through a shaft seal to a point externally of the device.

The expansible chamber device of the present invention is provided with a sealing arrangement in which (I) the high pressure fluid is transferred across only one pair of relatively movable surfaces which are the surfaces of a valve, (2) the valve surfaces are biased together by the pressurized operating fluid, (3) the inlet and outlet ports are reversible from the standpoint that either port may be used as the inlet port to obtain a desired direction of rotation without adversely affecting the operativeness of the sealing arrangement, and (4) the forces developed for biasing the valve into sealing engagement are only slightly larger than the axially directed opposing forces regardless of the direction of rotation of the device.

The object of the invention is to provide an expansible chamber type of device having a new and improved valve biasing the sealing arrangement.

Other objects and advantages of the invention will become apparent from the following specification, drawings and appended claims.

In the drawings:

FIG. 1 is a longitudinal sectional view of a fluid pres sure device embodying the invention, taken on line I-I of FIG. 3;

FIG. 2 is a slightly enlarged transverse sectional view taken on line IIlI of FIG. 1;

FIG. 3 is a transverse sectional view taken on line III- --III of FIG. 1; and

FIG. 4 is a fragmentary sectional view similar to the right hand end of FIG. 1 but altered to illustrate a modification of the invention.

In the illustrated embodiment of the invention there is provided a casing assembly comprising a generally cylindrically and annularly shaped shaft housing 2, a cylindrically shaped spacer disk 3, a cylindrically shaped gerotor section 4, acylindrically and annularly shaped valve block section 5 and a cylindrically shaped valve housing section 6. Casing sections 2 to 6 are held together in axial alignment by a plurality of circumferentially spaced bolt means in a known manner.

With reference to FIG. 2, the gerotor casing section 4, which may be referred to as a ring member 4, has a plurality of internal teeth 16. An externally toothed star member 18, having at least one fewer teeth than ring member 4, is disposed eccentrically in the chamber of space formed and surrounded by ring member 4. Star member 18 is movable in an orbital path about the axis 24 of ring member 4 and rotates about its own axis 25. During orbital movement of star member 18 the teeth 20 thereof intermesh with the ring member teeth 16 to form expanding and contracting cells 21 which are equal in number to the number of teeth 20 of star mem ber 18.

The generally cylindrically shaped shaft housing 2, has an axial bore 26 concentric with axis 24. An end cap 27 is connected to shaft housing 2 and has an axial opening 29 adapted to receive an output shaft 35. Output shaft 35 is positioned in shaft housing 2 for rotation within bore 26 about axis 24. Bearing assemblies 39 and 40 are positioned in housing 2 to receive shaft 35. Shaft 35 has an internal, axially extending receiving bore 43.

The shaft connection between the star gear 18 and the output shaft 35 is provided by a universal type of drive or wobble shaft having splined end portions 46 and 47. Output shaft 35 has an internal spline 48 which is engaged by the splined end 46 of the shaft 45. The splined portion 47 of shaft 45 meshes with an internal spline 50 of the star gear member 18.

Casing section 6 is cylindrically shaped and has an internal bore 52. Rotatably journalled in valve casing section 6 for rotation about the main axis 24 of the motor is a valve 54. Valve 54 is illustrated as having an internally splined central bore 55 opening towards valve block 5. Valve 54 is illustrated as being journalled relative to and having rotary sliding engagement with casing bore 52 but the precise mounting arrangement is entirely optional.

Valve block 5 has a central bore 57 and valve 54 has a radially extending, annularly shaped surface 58 which is cooperable in rotational sliding engagement with the adjacent radially extending, annularly shaped surface 59 of valve block 5. The enclosure defined by valve block 5 and easing section 6 defines a valve chamber 60.

A drive or wobble shaft 62 extends through valve block bore 57 and mechanically connects star 18 and valve 54 in driving relation. Heads 63 and 64 at opposite ends of shaft 62 are splined with the head 63 having meshing engagement with the internal spline 50 of star 18 and head 64 having meshing engagement with the internal spline 55 of valve 54. Valve 54, by reason of the shaft connection between it and star 18, will rotate at the same speed as the star 18 but in the opposite direction from the orbiting direction of the star 18. Shaft 35 will, for the same reason, rotate at the same speed as star 18 but in the opposite direction from the orbiting direction of star 18.

Valve block 5 is provided with inlet and outlet ports 66 and 67, either of which may be the inlet or the outlet. Valve 54 and valve block 5 are provided with fluid passage means, which are described in detail further on herein, through which fluid is conveyed from the port 66 or 67 to the cells 21 of the gerotor and returned to the other of the ports 66 or 67. Ports 66 or 67 will be the inlet depending on the direction of rotation desired for shaft 35.

Recessed inner and outer annular channels 73 and 74 are provided in the face 58 of valve 54 which are concentric relative to ring axis 24. Either or both of the channels 73 and 74 may be in either the face 59 of valve block 5 or the face 58 of valve 54 although both With reference to FIG. 3, valve 54 has a plurality of radially extending, circumferentially arranged and spaced grooves which are illustrated herein as a set of six grooves 78 which intersect and are in fluid communication with annular channel 73 and a set of six grooves 80, alternately spaced relative to grooves 78, which intersect and are in fluid communication with annular channel 74. In the fluid pressure device illustrated the grooves 78, and the grooves 80 are equal in number to the number of teeth 20 on the star 18.

Casing section 5 has a plurality of generally axially extending, circumferentially arranged and spaced passages 82 illustrated as being seven in number which is equal to the number of teeth 16 of the ring member 4. Passages 82 open into the radial face 59 of casing section 5 which face slidingly engage the radial face 58 of valve 54.

Upon rotation of valve 54, each of the grooves 78 and 80 thereof successively registers in fluid communication with each of the passages 82 in casing section 5. Fluid is supplied to and withdrawn from the gerotor through passages 82 which terminate at points which constitute junctions (see FIG. 2) between the teeth 16 of ring member 4.

Assuming that the fluid pressure device is functioning as a motor, pressurized fluid may be introduced into port 66 or port 67, depending on the direction of rotation desired for shaft 35. Assuming fluid is introduced into port 66, it would flow from there through casing passage 76 to annular channel 74 and all of the grooves 80 in valve 54, through certain of the passages 82 in casing section 5 on the right sideof the line of eccentricity 84 as viewed in FIG. 3, to certain gerotor cells 21 which, for an instant, as viewed in FIG. 2, are on the left side of the line of eccentricity 84. The expansion of the cells 21 on the left side of the line of eccentricity 84 causes star 18 to orbit in a clockwise direction and causes collapsing of the cells 21 on the right side of the line of eccentricity 84. Fluid from the collapsing cells 21 flows through casing passages 82 on the right side of the line of eccentricity 84, as viewed in FIG. 2 (on the left side of the line of eccentricity as viewed in FIG. 3) through annular channel 73 to passage 75 and out port 67. The above description of fluid flow is only for an instantaneous condition in that the line of eccentricity 84 rotates about the axis 24 of ring member 4. As long as pressurized fluid is admitted through port 66, however, the pressurized fluid will always be admitted to cells 21 on the same side of the line of eccentricity 84 and fluid will always be exhausted on the other side of said line.

Valve 54 is a cornmutating type valve in that it rotates at the same speed the star 18 rotates but it functions to supply and exhaust fluid to and from the gerotor at the orbiting frequency of the star.

Valve 54 is illustrated with a known type of fluid flow distribution pattern (referred to herein for convenience as FFDP) formed in the valve face 58 as may be best seen in FIG. 2. The FFDP of any valve used must have separate and distinct fluid feeding and exhausting sections and either of such sections will be the feeding section (and the other and exhausting section) depending upon which of the ports 66 or 67 is the inlet port. In valve 54, feeding and exhausting sections are formed with two sections 73, 78 and 74, 80 which are recessed relative to the valve face 58. Assuming port 66 to be the inlet port, section 74, 80 will be the feeding section and section 74, 78 will be the exhausting section.

If port 66 is used as the inlet port, valve block pas sages 66 and 76 and valve section 74, 80 form fluid inlet path means; concomitantly. valve section 73, 78 and valve block passages and 67 form fluid outlet path means. If port 67 is used as the inlet port, valve block passages 67 and 75 and valve section 73, 78 form fluid inlet path means; concomitantly, valve section 74, 80 and valve block passages 76 and 66 form fluid outlet path means.

Reference is now made to the manner in which the valve 54 is biased into sealing engagement with the face 59 of valve block 5. For this purpose there are provided restrictor passages 91 to 94 in the casing sections 5 and 6 which extend from the inlet and outlet passages or ports 66 and 67 to the valve chamber 60.

A restrictor passage, as that term is used herein, means a relatively small fluid flow passage which presents substantial resistance to the flow of pressurized fluid therethrough so as to effectively throttle the flow of fluid. As illustrated, restrictor passages 93 and 94 have check valves 96 and 97 which prevent the flow of fluid through these passages from the ports 66 and 67 a into the chamber 60. The restrictor passages 91 to 94 and the check valves 96 and 97 are shown in a more or less schematic form in that it is their functions rather than the specific forms they take that is of importance as far as the invention is concerned.

The matter of biasing the valve 54 is intimately related to the configuration of the fluid pressure distribution pattern defined between the faces 58 and 59 of the valve 54 and the valve block 5. In the illustrated embodiment of the invention the recessed annular feeding and exhausting channels 73 and 74, and the respectively associated grooves 78 and 80, are of unequal area and the unequalness of these areas is of significance. The area of annular channel 73 and the associated grooves 78 is about 20 percent of the area of the surface 100 on the opposite side of the valve. The area of annular channel 74 and the associated grooves 80 is greater by reason of having a greater diameter and is about 30 percent of the area of the valve surface 100.

Depending on whether pressurized fluid is admitted to the port 66 or the port 67, the force biasing the valve 54 to the right will be proportional to either the combined area of channel 73 and the associated grooves 78 or the combined area of channel 74 and the associated grooves 80. If pressurized fluid having the same pressure as the inlet pressure were admitted to the valve chamber 60, the pressure acting over the whole area of the rear valve surface 100 would result in a force biasing the valve to the left which will be on the order of three to five times greater than the force biasing it to the right. This would result in a net force to the left which would cause a substantial resistance to turning the valve and substantial wear to the valve surface 58.

Assuming that pressurized fluid is admitted through port 66, pressurized fluid in annular channel 74 and grooves 80 would react against the valve block 5 to bias the valve towards the right with a force corresponding to 30 percent of the valve area 100. If only restrictor passages 91 and 92 were present, and each such passage had a restrictor value of unity, the pressure drops across the restrictor passages 91 and 92 would be equal and the pressure in the chamber 60 would be about one-half the pressure of pressurized fluid in port 66. By

way of comparison, one-half the supply pressure acting over the entire area of valve surface 100 results in a force which is substantially greater than the opposing force which results from substantially the full supply pressure in annular channel 74 and grooves 80 acting on an area which is only 30 percent of the area on the front side of the valve 54.

In order to achieve precise balancing of the opposing forces there must be a still lower pressure in chamber 60 and such a lower pressure is achieved by adding the restrictor passage 94. If the supply pressure were 1000 psi, a pressure of 300 psi in chamber 60 would cause the opposing forces to be approximately equal. This pressure of 300 psi may be realized by making the combined restrictor value of the parallel restrictors 92 and 94 equal to three-sevenths of the restriction value of restrictor passage 91. Assuming restrictor passages 91 and 92 each has a relative value of unity, the value of restrictor passage 97 would be three-fourths of unity.

When reversed operation is desired, pressurized fluid is admitted to port 67. The annular channel 73 and the associated grooves 78 would be pressurized and a force corresponding to about percent of the valve area 100 would bias the valve towards the right. Assuming again that the supply pressure is 1,000 psi, a pressure of 200 psi in chamber 60 would cause the opposing forces to be approximately equal.

With pressurized fluid admitted to port 67, restrictor passage 94 is made ineffective by providing the check valve 97 therein which allows fluid flow out of the chamber 60 to the port 67 but prevents flow into the chamber. With restrictor passage 94 being inactive, a pressure of 200 psi in chamber 60 is realized by making the combined restriction value of the parallel restrictors 91 and 93 equal to one-fourth the restriction value of restrictor passage 92. If restrictor passages 91 and 92 each had a relative value of unity, the value of restrictor passage 93 would be one-third of unity.

Restrictor passage 93 is provided with check valve 96 so that restrictor passage 93 is ineffective when pressurized fluid is supplied to port 66 in the same manner that restrictor passage 97 is made inactive when pressurized fluidis supplied to port 67.

Referring to FIG. 4, the fragmentary section thereshown has elements corresponding generally to elements of the unit shown in FIG. 1 and such corresponding elements are referenced with the same numerals increased by one hundred.

In FIG. 4, there is shown a valve housing section 106 which is similar to the corresponding valve housing section 6 of the invention embodiment shown in FIG. 1. The difference generally is that one way valves 196 and 197 in restrictor passages 191 and 192 are oppositely positioned so that they permit the flow of pressurized fluid into the valve chamber but prevent the flow of fluid out of the chamber.

The arrangement of F IG. 4. is to provide for precisely determined pressures for the valve chamber which are greater than 50 percent of the value of the supply pressure. Assuming that the resistance values of restrictors 191 and 192 are equal, the total resistance to the flow of fluid through restrictors 191 and 193 is less than the resistance presented by restrictor 192 and hence the pressure in the valve housing will be greater than 50 percent of the supply pressure by any desired amount.

The restrictor passages 91 to 94 and 191 to 194 could be provided in the valve instead of the casing in the event that circumstances would make such a design feasible or desirable. From the standpoint of the theory of the invention it is only important that one set of restrictor passages be provided between the inlet flow path and the chamber and that another set of restrictor passages be provided between the outlet flow path and the chamber 60. As explained above, the inlet and outlet flow paths extend from the inlet casing passages to the inlet valve passages and from the outlet valve passages to the outlet casing passages. It will thus be understood that the inlet and outlet flow paths include the movable valve passages as well as the stationary casing passages.

In the operation of the device, pressurized fluid admitted through the port 66 or 67 and exhausted through the opposite port supplies the energy for driving the shaft 35 through the gerotor mechanism in a known manner as described. A novel innovation, however, is in the use of restrictor passages for pressurizing the valve chamber 60 to predetermined intermediate values which provide precise balancing of the valve 54 regardless of which port 66 or 67 is used as the inlet port. The restrictor passages may take various forms and may even be large passages equipped with throttle valve means which substantially restrict the flow of pressurized fluid through the passages. By way of example, it is expected that the flow rate of fluid through the restrictor passages may be on the order of 1 percent or less of the flow rates through the ports 66 and 67 but practical design considerations may require some deviation from these anticipated values.

I claim:

1. A fluid pressure operated device of the expansible chamber type comprising a casing, expansible chamber means, a valve block having a fluid transfer surface, said valve block having a plurality of expansible chamber feeding and exhausting passages having fluid communication with said expansible chamber means and having openings in said transfer surface, a valve having a surface engaging said transfer surface, said valve surface having recessed feeding and exhausting sections,- reversible inlet and outlet passages in said valve block having openings in said transfer surface and respective constant fluid communication with said feeding and exhausting sections of said valve, said valve block inlet passage and said valve feeding section forming fluid inlet path means, said valve block outlet passage and said valve exhausting section forming fluid outlet path means, said valve being cyclically movable relative to said transfer surface with said feeding and exhausting sections thereof sequentially feeding and exhausting said expansible chamber passages, said casing forming a valve biasing pressure chamber for said valve, first restrictor passage means between said inlet path and said chamber and second restrictor passage means between said outlet path and said chamber to provide a predetermined valve biasing pressure in said chamber intermediate the fluid pressures in said inlet and outlet passages, the magnitude of said biasing pressure being dependent on which one of said reversible inlet and outlet passages is used as an inlet passage, said first and second restrictor passage means each including at least two passages with at least one passage thereof being a one-way passage and at least one other passage thereof being a two-way passage and drive means between said expansible chamber means and said valve.

2. A fluid pressure device according to claim 1 wherein each of said one-way passages precludes the flow of fluid therethrough into said chamber.

3. A fluid pressure device according to claim 1 wherein each of said one-way passages precludes the flow of fluid therethrough out of said chamber. 

1. A fluid pressure operated device of the expansible chamber type comprising a casing, expansible chamber means, a valve block having a fluid transfer surface, said valve block having a plurality of expansible chamber feeding and exhausting passages having fluid communication with said expansible chamber means and having openings in said transfer surface, a valve having a surface engaging said transfer surface, said valve surface having recessed feeding and exhausting sections,reversible inlet and outlet passages in said valve block having openings in said transfer surface and respective constant fluid communication with said feeding and exhausting sections of said valve, said valve block inlet passage and said valve feeding section forming fluid inlet path means, said valve block outlet passage and said valve exhausting section forming fluid outlet path means, said valve being cyclically movable relative to said transfer surface with said feeding and exhausting sections thereof sequentially feeding and exhausting said expansible chamber passages, said casing forming a valve biasing pressure chamber for said valve, first restrictor passage means between said inlet path and said chamber and second restrictor passage means between said outlet path and said chamber to provide a predetermined valve biasing pressure in said chamber intermediate the fluid pressures in said inlet and outlet passages, the magnitude of said biasing pressure being dependent on which one of said reversible inlet and outlet passages is used as an inlet passage, said first and second restrictor passage means each including at least two passages with at least one passage thereof being a one-way passage and at least one other passage thereof being a two-way passage and drive means between said expansible chamber means and said valve.
 1. A fluid pressure operated device of the expansible chamber type comprising a casing, expansible chamber means, a valve block having a fluid transfer surface, said valve block having a plurality of expansible chamber feeding and exhausting passages having fluid communication with said expansible chamber means and having openings in said transfer surface, a valve having a surface engaging said transfer surface, said valve surface having recessed feeding and exhausting sections,reversible inlet and outlet passages in said valve block having openings in said transfer surface and respective constant fluid communication with said feeding and exhausting sections of said valve, said valve block inlet passage and said valve feeding section forming fluid inlet path means, said valve block outlet passage and said valve exhausting section forming fluid outlet path means, said valve being cyclically movable relative to said transfer surface with said feeding and exhausting sections thereof sequentially feeding and exhausting said expansible chamber passages, said casing forming a valve biasing pressure chamber for said valve, first restrictor passage means between said inlet path and said chamber and second restrictor passage means between said outlet path and said chamber to provide a predetermined valve biasing pressure in said chamber intermediate the fluid pressures in said inlet and outlet passages, the magnitude of said biasing pressure being dependent on which one of said reversible inlet and outlet passages is used as an inlet passage, said first and second restrictor passage means each including at least two passages with at least one passage thereof being a one-way passage and at least one other passage thereof being a two-way passage and drive means between said expansible chamber means and said valve.
 2. A fluid pressure device according to claim 1 wherein each of said one-way passages precludes the flow of fluid therethrough into said chamber. 